This application requests a renewal of funding for a training program in Investigative Dermatology at Columbia University, College of Physicians and Surgeons. The program is designed to produce independent investigators capable of designing and executing programs of excellence in dermatological research, both basic and clinically-oriented. This program rests on a foundation of well-funded research in the biology of skin diseases that includes 15 investigators with diverse areas of expertise, and $11,937,586 of annual direct costs from the National Institutes of Health. The participating faculty have research programs that include direct dermatological applications, and many have collaborative relationships with each other and within the University. Seven trainers are within the Department of Dermatology and eight other are from outside departments. The participating faculty also has strong training records for both pre-doctoral and postdoctoral candidates. State of the art technology is being used by all investigators to study some of the most complex problems in investigative dermatology at the mechanistic level. The training program has two specific aims: first, to give trainees a broad perspective on current knowledge and the major questions facing investigative dermatology; second to offer a wide choice of research training opportunities in investigative dermatology, using a variety of model systems, that will allow the development of a hypothesis-driven, mechanistically oriented research program suited to the individual trainee. The participating investigators are qualified to provide training in the different aspects of cutaneous biology and have well-developed research programs. Trainees will be selected on the basis of academic excellence, investigative ability, and commitment to a career in investigative dermatology. Selection will be made by a steering committee that will also monitor their progress. Interactions between investigators and trainees will be fostered during weekly and monthly research meetings where both trainers and trainees will present the results of experiments. While training in the Department of Dermatology, trainees will be enriched by the milieu of the College of Physicians & Surgeons, Columbia University. Finally, the research training experience of chosen candidates will include instruction in the responsible conduct of research as well as written and oral presentation of their work. In summary, they have a goal to capitalize on the strengths of the funded investigators in the Department of Dermatology, as well as the University, to provide trainees with a mentorship experience that is likely to lead to a career in investigative dermatology.